driscoll



Dec. 20, 1927. 1,653,395

J. F. DRlscoLl.

PAVEMENT Filed Feb. 25, 19?? lwenor e 8M ad@ to a downward pressure bymeans of a 'roller7 tainper or other suitable device, this pressurebeing` greater than the initial preesure previously applied to thelowerlayer alone and suflieiently heavy to compress both layers soeffectively that the two layers will be practically anialganieted ormerged into each other With no joint or division between them While atthe seine tinie both layers are condensed or compacted throughout theentire mess or thickness of the sei-rie, and thus liorin practically asingle layer Which is s u'lliciently rigid to resist wear and tear esWell as displacement.

It 'will be readily seen that in applying ay pressure by e roller ortamper which is suiliciently light to merely turn over or liutten theprojeeting` points or edges o'i the loose particles of rock appearing onor neer the surface of the bottoni course aiter it has been spread orraked, and while it still hot it .is possible to lay a sealing courseover the saine which is practically uniiforin in thiol;- ness, and intowhich no 1great ainount oi` rock is projecting.upwardly which otherwiseWould leave the upper sealing course thick in sonie places and ofpractically no thickness Whatever in others so tar es the upper layer isconcerned. 3y thus avoiding; sharp upward projections into the seel Coatoif the Wearing course of the pavement this seal coat is not liable tobecome indented by the tral'lic running` over the saine, nor start toWear unduly rapid at these points oi. inw dentation which Would permitdislodgeinent oiftlie rock or metal, but instead provides a unitorn'icovering over which the weight and Wear of the traliic is distributedevenly and repid deterioration is avoided.

By employing bitumen ot 'the suine com sisteney in both layers orCourses, 'the changes in temperature have the Serin-i eifeet on bothlayers, thereby avoiding any tendency el the tivo layers to seperate :iswould be the case it the bitumen in these layers were or diierentconsistency.

l claim as my inyentioir:

rllie liereindescribed method of making' a pavementrixl eh consists inlaying; ou the :foundation a lower body layer consistiiig` o i? amixture oli bi'tuniei., ay line mineral a" rrete and a course mineralagi' 'ite whiley this mi; yiure is hot; light rollin iis body layerWhile liot so a.:

i to moderately compact the saine and turn over the points oil any oithe course e 'regate which may project upwardly aitei seing; laid on theiburulatiou and thereby cause the course agl'srleoate to face upwarrfllywith its Wide sulla@ plying an upper linishiiig layer etiiisiilinggL ofbitumen and .line mineral aggregate While hot over said lower layerwhile the lutter is still liot; and their subjecting the upper and lowerlayers while still hot to a heavy these layers together into oneintegral mass in ivliieli no line of division present between the lowerand upper layers and the upper and lower suriieees of the paveu'ieut aresealed against the entrance ot water.

JAMES l?. 'DENK/ULL

